1. Field of the Invention
The present invention relates to a door unlocking system and a door unlocking method and, more particularly, relates to a door unlocking system and a door unlocking method to exclusively unlock some of a plurality of doors of a vehicle.
2. Description of the Related Art
A keyless entry system is known that unlocks doors of a vehicle by utilizing a wireless signal between a key carried by a user and a wireless device mounted on the vehicle. In this system, normally, when the user pushes an unlock button of the portable key, all the doors of the vehicle are unlocked. However, simultaneously unlocking all the doors leads to a security problem because, for example, when the user gets in the driver's seat, a suspicious person may enter the interior of the vehicle from the passenger's side of the vehicle.
In this regard, JP 2009-79418 A discloses a system changing the number of doors to be unlocked, based on positional information of a vehicle. This system enables provision of control such as unlocking only the door on the side of the driver's seat when it is determined that a vehicle is located in a relatively unsafe area, based on GPS information.
However, the system of JP 2009-79418 A uses GPS information and therefore has a complicated circuit configuration. Additionally, it is difficult to provide a boundary of safety around an area in which a vehicle is located and a risk of a suspicious person getting into a vehicle is not necessarily eliminated even in a safe area, resulting in a limited user's convenience.